Ceftaroline is a novel parenteral cephalosporin with a broad spectrum of activity against clinically important community-acquired and hospital-acquired Gram-negative and Gram-positive pathogens including methicillin-resistant Staphylococcus aureus and multidrug-resistant Streptococcus pneumoniae. 
U.S. Pat. No. 6,417,175 discloses compounds having excellent antibacterial activities for a broad range of Gram-positive and Gram-negative bacteria. These compounds are represented by the general formula:

wherein R1-R4, Q, X, Y and n are as defined therein.
U.S. Pat. No. 6,417,175 discloses methods for preparing the compounds, and generically discloses formulations of the compounds, such as aqueous and saline solutions for injection. One such compound is 7β-[2(Z)-ethoxyimino-2-(5-phosphonoamino-1,2,4-thiadiazole-3-yl)acetamido]-3-[4-(1-methyl-4-pyridinio)-2-thiazolythio]-3-cephem-4-carboxylate.
U.S. Pat. No. 6,906,055 discloses a chemical genus which includes compounds of formula:

Ceftaroline fosamil is a sterile, synthetic, parenteral prodrug cephalosporin antibiotic. The N-phosphonoamino water-soluble prodrug is rapidly converted into the bioactive ceftaroline, which has been demonstrated to exhibit antibacterial activity. Ceftaroline fosamil is known as (6R,7R)-7-{(2Z)-2-(ethoxyimino)-2-[5-(phosphonoamino)-1,2,4-thiadiazol-3-yl]acetamido}-3-{[4-(1-methylpyridin-1-ium-4-yl)-1,3-thiazol-2-yl]sulfanyl}-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate. Ceftaroline fosamil may be an acetic acid hydrous form.

U.S. Pat. No. 7,419,973 discloses compositions comprising ceftaroline fosamil and a pH adjuster, such as, L-arginine.
U.S. Pat. Nos. 6,417,175 and 6,906,055 and 7,419,973 are incorporated herein by reference, in their entirety.
There is an existing and continual need in the art for new and improved compositions comprising ceftaroline or a prodrug thereof and methods for treating bacterial infections by administering ceftaroline or a prodrug thereof. The present invention provides compositions and methods for treating bacterial infections using ceftaroline or a prodrug thereof (e.g., ceftaroline fosamil). These compositions and methods are surprisingly and unexpectedly effective in treating bacterial infections, such as complicated skin and structure infections (cSSSI) and community-acquired bacterial pneumonia (CABP).